Fig. 2.

ATP binds to bovine serum albumin (BSA). A ATP content of a BSA solution (1 mg/mL) treated with triton X-100-based lysis buffer (LB) and incubated with either apyrase (Apy) or inactivated apyrase. B ATP concentration of a BSA solution at different dilutions. C ATP content of fresh FBS sample (Gibco) after treatment with LB at neutral pH (7.8) and after induction of an acid shock. ATP was measured at acid pH (5.8) and then at restored neutral pH. D ATP content of BSA-depleted FBS (filtered FBS) and complete (BSA-containing) FBS exposed to acid shock. ATP was measured using soluble luciferase in all experiments